WITHIN UDDER INFECTIONS IN PREGNANT HEIFERS WHICH WERE HOUSED TOGETHER AND REARED ON FRESH MILK AS CALVES.

Discipline: mastitis; 

Heifers may calve down with within udder infections and udder damage. This obviously may have a negative impact on their longevity, future milk yield and the financial returns. Pre-weaned calves housed together (co-housed) that are fed fresh milk may suckle each other’s teats and may infect udders of fellow heifer calves with pathogens present in the milk. The question is how big a problem is this.  The investigation by the authors referenced below attempted to address the possibility, since the prevalence of within udder infections in pregnant heifers in South Africa which were co-housed and reared on fresh milk as calves, is not known. 

In the study, quarter secretion samples from 2065 pregnant heifers and 5365 dry cows were collected for microbiological analysis from eight dairy herds. All heifers tested in this study were co-housed before weaning and were fed fresh milk as calves. 

The prevalence of so-called coagulase negative staphylococci, Staphylococcus aureus, Streptococcus agalactiae, environmental streptococci and coliforms in heifers was 26%, 0.9%, 0.08%, 1.4% and 0.4% respectively, whereas samples with no bacterial growth were in the majority at 66%. The overall prevalence ratio between heifers and cows for Staph. aureus within udder infections was 0.76. Four of the individual herds had prevalence ratios of less than one, which was statistically significant, one herd had a prevalence ratio of 3.15, and the remaining three herds had a prevalence ratio not significantly different from 1.0. Marginally significant differences were found between Staph. aureus within udder infections in pregnant heifers compared to cows in their second and later lactations but no significant differences between heifers and cows in their first lactation. 

Quite surprising was the presence of Streptococcus agalactiae induced within udder infections in heifers, especially since total herd infection rates were low. The authors recommended that the high prevalence ratio of Staph. aureus between heifers and cows in the one herd should be investigated further because of the potential danger of udder damage in a young cow at the start of her productive life. The within udder infection in heifers with host-adapted pathogens can also act as a source of new within udder infections for lactating dairy cows.

Reference:

Petzer, I-M., Karzis, J., Lesosky, M., Watermeyer, J.C. &  Badenhorst, R., 2013. Host adapted intramammary infections in pregnant heifers which were co-housed and reared on fresh milk as calves. URI: http://hdl.handle.net/2263/21518